As renewable energy sources increase their penetration, the traditional providers of frequency regulation service, fossil fueled thermal power plants, will be displaced, motivating the search for novel providers such as demandside resources. This paper presents the results of field experiments using demand as a frequency controlled reserve (DFCR) on appliances with programmable thermostats. The experiments conducted showed the response of a populationof thermostatically controlled loads acting as normal reserves and disturbance reserves as defined by the Nordic Grid Codes [1]. In addition, industrial pump loads and relay-controlled loads were tested as DFCR. The tests show that a population of refrigerators was able to deliver frequency reserves approximately equal to their average power consumption. Electric space heaters were able to provide frequency reserves of over 90% their maximum power consumption in certain weather conditions.